Ammunition for 4.5 in naval gun 4.5 in Anti-Aircraft Practice (Flash) N5A2, fuzed N97

fulfilling a perceived future gun and ammunition requirement, Vickers Shipbuilding and Engineering Limited (VSEL) associated with PRB SA of Belgium, developed a 4.5 in round with a Base Bleed (BB) capability providing a range capability of 27,500 m. However, PRB ceased trading and it was not until 1993 that tenders were again invited for the development of an increased range 4.5 in round. The extended range ammunition will utilise an optimised fuze and feature improved fragmentation over existing rounds. Royal Ordnance (now BAE Systems , RO Defence), which already produces 4.5 in ammunition, is bidding to obtain a development and production contract for an improved HE round from the UK Ministry of Defence. RO Defence was awarded a £50 million plus design, development and production contract for the extended range HE round in July 1997. Available details for this round are provided below. The UK Design Authority for 4.5 in naval gun ammunition is RO Defence. Description The 4.5 in rounds for the Mk 8 naval gun are fixed, enabling them to be used with mechanical ammunition handling and loading systems. The projectiles are therefore rigidly secured to their brass cartridge cases by a series of three 360º crimping rings. However, some rounds have been produced as either fixed or separate loading rounds. The projectiles have thin-walled forged steel bodies, flat bases and a wide copper drive band. Short or deep intrusion fuzes can be installed. The rounds are normally delivered and stored inside special containers which can interlock for stacking. A special tool is used to remove the container lid and round. All 4.5 in rounds use a standard brass cartridge case containing MNLF/2P/M08 triple-base propellant and have an N44 series electrical primer. All rounds are 1.238 m long overall. Among the types of round available or in service are the following: 4.5 in HE N1A4, fuzed N97 This is a general-purpose high blast and fragmentation round, usually fitted with a general purpose proximity and direct action fuze. Available as a fixed round only. The French TDA UA 3020 (USFA) proximity fuze may be used with this round. The Royal Navy expressed a requirement for 1,548 of these rounds for the FY94-95. Royal Ordnance 4.5 in HE ER Royal Ordnance have proposed an improved 4.5 in HE ER round which will embody changes to the projectile to improve the shape and incorporate a Base Bleed (BB) unit to extend the maximum range. Changes to the propellant, projectile steel and the type of fuze are anticipated. It is intended that the fixed round will be compatible with the current ammunition packaging and gun system. Available details are that the projectile will weigh 20.6 kg and contain 3 kg of RDX/TNT (60/40); the fuze will weigh less than 1 kg. The cartridge case will contain 7.15 kg of propellant producing a muzzle velocity of 869 m/s. Round length will be 1.238 m. 4.5 in Star N4A1, fuzed N9 Mk 1 Fitted with a mechanical time fuze, this round provides target or other illumination for approximately 40 seconds. Known as `Monica' or, more generally, Star. 4.5 in Radar Echo (RE) Produced in two forms, RE/J and RE/I, this round fires a projectile which dispenses its chaff payload to jam or confuse enemy radars. Fitted with an N9 Mk 2 mechanical time fuze. 4.5 in Anti-Aircraft Practice (Flash) N5A2, fuzed N97 Known as AAP, this relatively low-cost round is used for anti-aircraft or other practice firings. The normal fuze is a general purpose proximity and direct action type which, on functioning, uses its exploder to produce a small flash to indicate fuze or projectile functioning. The filling is an inert material. 4.5 in Surface-Use Practice N7A2 Intended for practice firing against surface targets, this projectile has the same body as the HE round but is filled with an inert material and a nose plug representing a fuze (PRF). This round is known as SUP. The Royal Navy expressed a requirement for 1,944 of these rounds for the Fiscal Year 1994-95. 4.5 in Radar Enhanced N13A1 The projectile used with this round is inert but the nose section contains extra radar reflectors enabling it to be used as a simulated anti-ship missile target for training with missile fire-control systems. 4.5 in Ram Rounds These are completely inert non-firing, one-piece rounds intended for cycling through ammunition feed systems or for general handling training. An inert test fuze for use with fuze setting mechanisms may be fitted. Authorised fuzes Various - see text Equivalent rounds BRAZIL BRAZIL Manufacturer FI Indústria e Comércio Ltda Type: HE, SUP, SAP, AAP, Illum Description: Standard specifications NETHERLANDS Manufacturer Eurometaal NV Type: HE, AAP, SUP Description: Standard specifications